Thursday, March 19, 2009

Wild fish vs. farmed fish


Time for a battle royal, a smackdown over who's the real sustainable source of fish, fishing or fish farms.

Right now, fishing has the moral high ground with stories on contamination in farmed fish and ocean harm from fish farms. But aquaculture is making a strong push with economic clout and improving technology, and the acccurate pitch that the world needs farmed fish.

Now a fish farming business is making a run at the moral high ground of sustainability, with a striking new argument that actually rings true to me.

Does fishing really have less impact on oceans than fish farming? Many ocean people make this claim, often in a blanket way as though fish farming is always bad. From my perspective, badly-managed fishing is clearly worse than a good fish farm. And, I think for good fish farms and good fishing it's not clear which is worse for the ocean.

One point rarely raised is that fish caught in the wild are eating a lot of forage and may have more ecological impact on forage fish than capture for fish farming. I know some will say "that's ok, because it's natural impact" but that argument doesn't sway me.

Kona Blue, purveyors of sustainable farmed fish, want you to think about these questions. According to The Earth Times, they've just released a new report that includes some provocative claims about how farmed fish are often much more sustainable than wild fish. I'm trying to track down the original report for you, and I'll offer more when I've had a chance to dig in. Stay tuned, this issue is going to grow in importance.

Here's Kona Blue, quoted in The Earth Times.

“If we examine the true environmental cost of wild-caught predatory fish -- such as swordfish or tuna -- we find sustainably maricultured fish have some 60 times less impact on fish stocks at the base of the food chain, such as sardines and anchovies,” said Neil Anthony Sims, President of Kona Blue. The leading offshore mariculture operation in the U.S., Kona Blue raises sashimi-grade Kona Kampachi®, a Hawaiian yellowtail, off the coast of Hawaii.

“What would ocean-conscious consumers rather have on their plates?” asked Sims. “One pound of Kona Kampachi®, or one sixtieth of a pound of tuna? The impact on the oceans is about the same.”

Sims bases this estimate on three primary considerations. First, aquaculture is continually moving towards sustainable substitutes in farmed fish diets to lessen reliance on fishmeal and fish oil. Kona Blue’s current feed formulation includes only 35% fishmeal/fish oil from wild baitfish, of which approximately 3% is from capture fishery by-product. Contrary to outdated ratios of 5:1 or higher quoted by some environmental groups, the current ratio of “wild fish in to farmed fish out” has fallen to approximately 1.5:1 (1.5 lbs. of anchovies producing 1 lb. of sashimi-grade farmed fish).

By contrast, wild fish are subject to the laws of trophic transfer, where only 10% of their prey’s food value is transferred up each step of the food chain. “If a tuna eats a mackerel that earlier ate an anchovy, then there are two trophic steps, compounding the costs,” said Sims. “A tuna may therefore need to eat the equivalent of 100 pounds of baitfish to increase its weight by one pound.” As the fishmeal/fish oil for farmed fish feed involves only one efficient step, trophic transfer loss is minimized.

7 comments:

Paul and Deb said...

Don't eat any fish - problem solved. Sorry, but..."Our task must be to free ourselves . . . by widening our circle of compassion to embrace all living creatures and the whole of nature and its beauty."
"Nothing will benefit human health and increase chances of survival for life on earth as much as the evolution to a vegetarian diet."
Albert Einstein, physicist, Nobel Prize 1921

Anonymous said...

Thanks Mark for another thought provoking post. As this is relevant to our blog as well, we have posted on our site with many links to your blog.
Please keep it up.

http://alaskasalmonranching.wordpress.com/2009/03/21/blogfish-wild-fish-vs-fish-farms/

WhySharksMatter said...

Fish farming initially had environmental problems, but amazing advances are being made every day.

Wild fish stocks won't support a growing world population.

Fish farming is the future.

"Don't eat any fish" is a pithy and underthought response.

tres_arboles said...

Another great post, Marc. After two days out on the mid-channel bank this weekend, all I have to say is "What wild fish?" I fished with two guys who were among the group that helped perfect the winter blackmouth fishery, and we didn't even mark a fish in two days, let alone hook-up.

But seriously, as you might be aware, NMFS consulted with EPA last year on farming in Puget Sound and found, using the best available science, that the environmental effects of fish farming are not likely to adversely affect ESA-listed animals of any kind in Puget Sound. Farming practices are as sound as they've ever been, and as long a you don't have to ship the product thousands of miles, this might end up being a wonderful regional source of protein. Even so, EPA has been sued for permitting the operations.

At Paul and Deb: C'mon guys. No disrespect, but changing the subject doesn't make an argument.

Anonymous said...

I don't doubt that in the long run, a diversity of sustainable farmed seafood will be necessary, barring catastrophic population reductions. But it's not clear to me that the article was a step in the right direction.

Instead of reducing the argument to one variable (i.e.trophic transfer), the type of oversimplification is what has gotten us into trouble in the first place, I'd like to see the trophic transfer presented as one term in a larger equation -- and some indication what the other terms and coefficients are so that we can have a sense of how big a role it plays in the big picture. I know it's not easy, so we also need an ecosystem picture of the interrelatedness of the various terms. Then to put that in context, we need some confidence intervals to represent our real levels of ignorance about how our ecosystems really work.

I know that's a lot to ask, but indeed many of today's scientists are looking at things from that sort of holistic point of view and basing their judgements on simulations rather than on rhetoric. Now's a good time for our journalists to get creative with inventing prose styles to convey the meat of that complexity in a useful way without publishing tomes that the readers won't read, and without just pulling "the most important" variable out of the mix for the sake of making a simple, sensational headline story.

Mark Powell said...

Good comments, folks. I agree that salmon farming in Puget Sound is not a big deal, because there are not many farms. And anonymous, you have a great suggestion for how to look at forage fish impacts in a larger context, I wish we had available the analysis you outlined. When will you have it done?

gamefan12 said...

I definitely like the wild fish compared to the farm fish. I am not sure why they do this. This is something that needs to be left in the wild.
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